Breaking his silence on the rape-murder of a minor in Jammu and Kashmir and the rape of another in Uttar Pradesh, Prime Minister Narendra Modi on Friday promised justice and said the incidents that have caused outrage have shamed the country.

Modi's comments came at a function in New Delhi hours after the Central Bureau of Investigation (CBI) got into the act by detaining and questioning rape accused BJP MLA Kuldip Singh Sengar in Uttar Pradesh while two BJP Ministers in the Jammu and Kashmir coalition led by the PDP resigned for taking part in a rally in support of the accused in the ghastly rape-and-murder of an eight-year-old girl.

"The incidents that are in discussion in the country for the last two days do not reflect good for any civilised country. This is shameful," Modi said after widespread outrage over the incidents in Kathua in Jammu and Kashmir and Unnao district in Uttar Pradesh.

"It's an insult to freedom fighters who gave their lives for the independence of this country. We are all ashamed as a society, as a country," Modi said, speaking at the inauguration of the Ambedkar National Memorial in New Delhi.

"Such incidents in any part of the country or a state shake humanity. I want to assure the country that no culprit will escape. Justice will be done and it will be complete justice. The daughters will get justice. We all will have to join hands and remove this evil from the society."

In January, an eight-year-old girl went missing while grazing horses in Rassana forest in Kathua. A week later, her raped and battered body was recovered. Investigations revealed she was held captive in a temple and was sedated before being repeatedly raped and murdered.

Two BJP ministers Choudhary Lal Singh and Chander Prakash Ganga, who attended a rally in support of the Kathua accused last month, resigned from the Jammu and Kashmir government led by Chief Minister Mehbooba Mufti.

Singh, who held the Environment and Forest portfolio and Ganga, the Industries and Commerce Minister, submitted their resignations to state BJP chief Satpal Sharma.

They had sparked overwhelming public outcry after attending a rally in Hiranagar area of Kathua district organised by the Hindu Ekta Munch in favour of the seven people accused in the rape and murder of the minor.

In New Delhi, the BJP appeared to be on the back foot, with its MP and spokesperson Meenakshi Lekhi admitting that the two BJP ministers in Jammu and Kashmir had committed a wrong by taking part in the rally.

She, however, said they were "misled and misguided" by people and accused the Congress of communalising the rape incidents.

"When you are in public life, people come to you with their version... So, the lesson to them is not to believe one side or the other and let the law take its course."

In Unnao, a 17-year-old was raped last year allegedly by BJP MLA Kuldeep Sengar, who was named in a CBI FIR and questioned on Friday.

The incident came to light after the victim tried to set herself ablaze outside Chief Minister Yogi Adityanath's residence on Sunday.

The family has alleged that the police refused to file an FIR. The victim's father died after being allegedly beaten by the MLA's brother and aides at a police station.

The CBI filed three FIRs late on Thursday over the rape and the victim's father's death in police custody. Phone call details of the accused legislator have also been sought.

In the first FIR, the CBI named Sengar and Shashi Singh, a woman who allegedly took the rape victim to the Bharatiya Janata Party leader's house.

The second FIR is against four of Sengar's accomplices -- Vineet, Baua, Shailu and Sonu -- on charges of rioting, criminal intimidation and voluntarily causing hurt.

The third one relates to Sengar's brother Atul Singh, who claimed that he was attacked by the victim's father. Atul Singh is currently in judicial custody.